Heating, ventilation, and air conditioning (HVAC) systems can be used to maintain temperatures of zones (e.g., rooms, hallways). The HVAC system can include a heating and/or cooling unit in communication with a sensor and/or user interface (e.g., thermostat), which can be used to control the HVAC system.
The HVAC system can be programmed to cool and/or heat a zone to a particular temperature during a particular time of day. In an example, during a period of the day when the zone is unoccupied, the HVAC system can be set to a passive mode, in which minimal cooling and/or heating is performed by the HVAC system. This can allow for the temperature of the zone to drop and/or rise.
When the zone becomes occupied, it can be desirable to cool and/or heat the zone to a particular temperature that is within a thermal comfort zone. As such, energy can be saved on cooling and/or heating when the zone is unoccupied. Alternatively, and/or in addition, the zone can be maintained at a temperature in the thermal comfort zone when the zone is occupied.
However, challenges can be associated with bringing the zone to a temperature within the thermal comfort zone at a time when the zone becomes occupied. For example, in a zone that is being heated, the temperature can be increased to a temperature that is above a minimum temperature of the thermal comfort zone, at the moment the zone becomes occupied and/or at a moment before the zone becomes occupied, thus wasting energy. Alternatively, and/or in addition, the temperature may not reach a minimum temperature of the thermal comfort zone at the moment the zone becomes occupied, which can cause discomfort to the occupants of the zone.